path: root/src/org/apache/fop/fo/SVGTreeBuilder.java

/* $Id$
 * Copyright (C) 2001 The Apache Software Foundation. All rights reserved.
 * For details on use and redistribution please refer to the
 * LICENSE file included with these sources."
 */

package org.apache.fop.fo;

// FOP
import org.apache.fop.fo.*;
import org.apache.fop.svg.*;
import org.apache.fop.layout.AreaTree;
import org.apache.fop.messaging.MessageHandler;
import org.apache.fop.apps.FOPException;
import org.apache.fop.fo.pagination.Root;

// SAX
import org.xml.sax.helpers.DefaultHandler;
import org.xml.sax.SAXException;
import org.xml.sax.InputSource;
import org.xml.sax.Attributes;

import org.w3c.dom.svg.*;

// Java
import java.util.Hashtable;
import java.util.Stack;
import java.io.IOException;

// NOTE: This class is here since a number of FObj methods that
// are called are protected. This should probably be fixed.
/**
 * SAX Handler that builds the formatting object tree.
 */
public class SVGTreeBuilder extends DefaultHandler implements TreeBuilder {

    /**
     * table mapping element names to the makers of objects
     * representing formatting objects
     */
    protected Hashtable fobjTable = new Hashtable();

    /**
     * class that builds a property list for each formatting object
     */
    protected Hashtable propertylistTable = new Hashtable();

    /**
     * current formatting object being handled
     */
    protected FObj currentFObj = null;

    /**
     * the root of the formatting object tree
     */
    protected FObj rootFObj = null;

    /**
     * set of names of formatting objects encountered but unknown
     */
    protected Hashtable unknownFOs = new Hashtable();

    // namespace implementation ideas pinched from John Cowan
    /*    protected static class NSMap {
    	String prefix;
    	String uri;
    	int level;

    	NSMap(String prefix, String uri, int level) {
    	    this.prefix = prefix;
    	    this.uri = uri;
    	    this.level = level;
    	}
        }

        protected int level = 0;
        protected Stack namespaceStack = new Stack();

        {
    	namespaceStack.push(new NSMap("xml",
    				      "http://www.w3.org/XML/1998/namespace",
    				      -1));
    	namespaceStack.push(new NSMap("", "http://www.w3.org/2000/svg", -1));
        }

        protected String findURI(String prefix) {
    	for (int i = namespaceStack.size() - 1; i >= 0; i--) {
    	    NSMap nsMap = (NSMap) (namespaceStack.elementAt(i));
    	    if (prefix.equals(nsMap.prefix)) return nsMap.uri;
    	}
    	return null;
        }

        protected String mapName(String name)
    	throws SAXException {
    	int colon = name.indexOf(':');
    	String prefix = "";
    	String localPart = name;
    	if (colon != -1) {
    	    prefix = name.substring(0, colon);
    	    localPart = name.substring(colon + 1);
    	}
    	String uri = findURI(prefix);
    	if (uri == null) {
    	    if (prefix.equals("")) {
    		return "http://www.w3.org/2000/svg^" + name;
    	    } else {
    		throw new SAXException(new FOPException("Unknown namespace prefix " + prefix));
    	    }
    	}
    	return uri + "^" + localPart;
        }*/

    /**
     * add a mapping from element name to maker.
     *
     * @param namespaceURI namespace URI of formatting object element
     * @param localName local name of formatting object element
     * @param maker Maker for class representing formatting object
     */
    public void addMapping(String namespaceURI, String localName,
                           FObj.Maker maker) {
        this.fobjTable.put(namespaceURI + "^" + localName, maker);
    }

    /**
     * add a mapping from element name to maker.
     *
     * @param namespaceURI namespace URI of formatting object element
     * @param localName local name of formatting object element
     * @param maker Maker for class representing formatting object
     */
    public void addPropertyList(String namespaceURI, Hashtable list) {
        PropertyListBuilder plb;
        plb = (PropertyListBuilder) this.propertylistTable.get(
                namespaceURI);
        if (plb == null) {
            plb = new PropertyListBuilder();
            plb.addList(list);
            this.propertylistTable.put(namespaceURI, plb);
        } else {
            plb.addList(list);
        }
    }

    /**
     * add a mapping from element name to maker.
     *
     * @param namespaceURI namespace URI of formatting object element
     * @param localName local name of formatting object element
     * @param maker Maker for class representing formatting object
     */
    public void addElementPropertyList(String namespaceURI,
                                       String localName, Hashtable list) {
        PropertyListBuilder plb;
        plb = (PropertyListBuilder) this.propertylistTable.get(
                namespaceURI);
        if (plb == null) {
            plb = new PropertyListBuilder();
            plb.addElementList(localName, list);
            this.propertylistTable.put(namespaceURI, plb);
        } else {
            plb.addElementList(localName, list);
        }
    }

    /** SAX Handler for characters */
    public void characters(char data[], int start, int length) {
        currentFObj.addCharacters(data, start, start + length);
    }

    /** SAX Handler for the end of an element */
    public void endElement(String uri, String localName, String rawName) {
        currentFObj.end();
        currentFObj = (FObj) currentFObj.getParent();
        /*	level--;
         	while (((NSMap) namespaceStack.peek()).level > level) {
         	    namespaceStack.pop();
         	}*/
    }

    /** SAX Handler for the start of the document */
    public void startDocument() {
        MessageHandler.logln("building svg tree");
    }

    /** SAX Handler for the start of an element */
    public void startElement(String uri, String localName,
                             String rawName, Attributes attlist) throws SAXException {
        /* the formatting object started */
        FObj fobj;
        if (uri.equals("")) {
            uri = "http://www.w3.org/2000/svg";
        }

        /* the maker for the formatting object started */
        FObj.Maker fobjMaker;

        /*	level++;
        	int length = attlist.getLength();
        	for (int i = 0; i < length; i++) {
        	    String att = attlist.getQName(i);
        	    if (att.equals("xmlns")) {
        		namespaceStack.push( new NSMap("",
        					       attlist.getValue(i),
        					       level));
        	    } else if (att.startsWith("xmlns:")) {
        		String value = attlist.getValue(i);
        		namespaceStack.push(new NSMap(att.substring(6), value,
        					      level));
        	    }
        	}*/

        //	String fullName = mapName(rawName);
        String fullName = uri + "^" + localName;
        fobjMaker = (FObj.Maker) fobjTable.get(fullName);
        PropertyListBuilder currentListBuilder =
          (PropertyListBuilder) this.propertylistTable.get(uri);

        if (fobjMaker == null) {
            if (!this.unknownFOs.containsKey(fullName)) {
                this.unknownFOs.put(fullName, "");
                MessageHandler.errorln(
                  "WARNING: Unknown formatting object " + fullName);
            }
            fobjMaker = new FObjMixed.Maker(); // fall back
        }

        try {
            PropertyList list = null;
            if (currentListBuilder != null) {
                list = currentListBuilder.makeList(fullName, attlist,
                                                   (currentFObj == null) ? null :
                                                   currentFObj.properties, currentFObj);
            }
            fobj = fobjMaker.make(currentFObj, list);
        } catch (FOPException e) {
            throw new SAXException(e);
        }

        if (rootFObj == null) {
            rootFObj = fobj;
            if (!fobj.getName().equals("svg:svg")) {
                throw new SAXException(
                  new FOPException("Root element must" +
                                   " be svg, not " + fobj.getName()));
            }
        } else {
            currentFObj.addChild(fobj);
        }

        currentFObj = fobj;
    }

    /**
     */
    public SVGDocument getSVGDocument() {
        SVGDocument doc = null;
        /*    	doc = new SVGDocumentImpl();
                 SVGSVGElement svg = (SVGSVGElement)((org.apache.fop.svg.SVG)rootFObj).createGraphic();
                 doc.appendChild(svg);*/
        return doc;
    }
}